Does PowerShell support OOP? - oop

Question

What is about such concepts as Class, Interface, Mixin in PowerShell? Does it support OOP? If so, where can I read about this?

Answer 1

You can define new types in PowerShell v2.0 using the Add-Type cmdlet:
DETAILED DESCRIPTION
The Add-Type cmdlet lets you define a .NET class in your Windows PowerShell session. You can then instantiate objects (by using the New-Object cmdlet) and use the objects, just as you would use any .NET ob
ject. If you add an Add-Type command to your Windows PowerShell profile, the class will be available in all Windows PowerShell sessions.
You can specify the type by specifying an existing assembly or source code files, or you can specify source code in line or saved in a variable. You can even specify only a method and Add-Type will define
and generate the class. You can use this feature to make Platform Invoke (P/Invoke) calls to unmanaged functions in Windows PowerShell. If you specify source code, Add-Type compiles the specified source co
de and generates an in-memory assembly that contains the new .NET types.
You can use the parameters of Add-Type to specify an alternate language and compiler (CSharp is the default), compiler options, assembly dependencies, the class namespace, and the names of the type and the
resulting assembly.
help Add-Type for more information.
Also, see:
How do I create a custom type in PowerShell for my scripts to use?
http://thepowershellguy.com/blogs/posh/archive/2008/06/02/powershell-v2-ctp2-making-custom-enums-using-add-type.aspx

Answer 2

PowerShell is more of an OOP consumer language. It can utilize most of the .NET Framework but it doesn't natively support creating interfaces, classes and certainly not mixins. .NET, which PowerShell's type system is based upon, doesn't support mixins. PowerShell does support dynamic addition of properties and methods to an existing object via the Add-Member cmdlet.
Add-Type is useful but if you have to escape to C# or VB to define a class or a class that implements a particular interface, I wouldn't consider that first class support the creation of classes/interfaces.
If you looking for some free learning material, check out Effective Windows PowerShell.

Answer 3

Version 5 of Powershell seems to support some of mainstream OOP.
All credit goes to this guy: https://xainey.github.io/2016/powershell-classes-and-concepts/
Example of a class:
class myColor
{
[String] $Color
[String] $Hex
myColor([String] $Color, [String] $Hex)
{
$this.Color = $Color
$this.Hex = $Hex
}
[String] ToString()
{
return $this.Color + ":" + $this.Hex
}
}
Example of an abstract class:
class Foo
{
Foo ()
{
$type = $this.GetType()
if ($type -eq [Foo])
{
throw("Class $type must be inherited")
}
}
[string] SayHello()
{
throw("Must Override Method")
}
}
class Bar : Foo
{
Bar ()
{
}
[string] SayHello()
{
return "Hello"
}
}

Answer 4

The PowerShell pipeline deals with objects, not just a text stream a a Unix pipeline does. All variables are instances of objects as well. These are all .NET objects, BTW.
Here's part of the output of an "ls" command piped to the get-member cmdlet:
PS C:\Documents and Settings\Administrator.DEV-3DPST1-SWK> ls | get-member
TypeName: System.IO.DirectoryInfo
Name MemberType Definition
---- ---------- ----------
Create Method System.Void Create(DirectorySecurity directorySecurity), System.Void Create()
CreateObjRef Method System.Runtime.Remoting.ObjRef CreateObjRef(Type requestedType)
CreateSubdirectory Method System.IO.DirectoryInfo CreateSubdirectory(String path), System.IO.Director...
Delete Method System.Void Delete(), System.Void Delete(Boolean recursive)
Equals Method System.Boolean Equals(Object obj)
GetAccessControl Method System.Security.AccessControl.DirectorySecurity GetAccessControl(), System....
GetDirectories Method System.IO.DirectoryInfo[] GetDirectories(String searchPattern), System.IO.D...
GetFiles Method System.IO.FileInfo[] GetFiles(String searchPattern), System.IO.FileInfo[] G...
GetFileSystemInfos Method System.IO.FileSystemInfo[] GetFileSystemInfos(String searchPattern), System...
GetHashCode Method System.Int32 GetHashCode()
GetLifetimeService Method System.Object GetLifetimeService()
GetObjectData Method System.Void GetObjectData(SerializationInfo info, StreamingContext context)
GetType Method System.Type GetType()
get_Attributes Method System.IO.FileAttributes get_Attributes()
get_CreationTime Method System.DateTime get_CreationTime()
get-member displays the members of the object you pipe to it. You can see that these are the actual members of the System.IO.DirectoryInfo class.